Bondable orthodontic appliance with a polymer resin bonding base

ABSTRACT

An orthodontic appliance of the bracket or tube type for bondable mounting on a tooth including an appliance body having a buccal/labial archwire receiving side and a lingual side and a polymer resin bonding base molded to the lingual side such that at least part of the body is embedded in the base, and wherein the base may include openings for receiving an auxiliary or a secondary archwire.

This application is a continuation of my application Ser. No.10/244,770, filed Aug. 21, 2002, now U.S. Pat. No. 6,685,468.

This invention relates in general to an orthodontic appliance forbondable mounting on a tooth including a body and a polymer resinbonding base molded to the body, wherein the base includes an openingfor receiving the arm of an auxiliary or a secondary archwire, and alsoto an orthodontic appliance for mounting on a tooth including a metalorthodontic body and a polymer resin bonding base bonded to the body.

BACKGROUND OF THE INVENTION

Heretofore it has been well known to provide a bondable orthodonticappliance for mounting on a tooth, wherein the appliance includes a bodyand a bonding base attached thereto wherein the body includes an openingfor receiving an arm of an auxiliary such as an uprighting spring.

It is also well known to provide bondable orthodontic appliances formounting on teeth, such as brackets with or without vertical openings orslots. In the profession, the demand for brackets with or withoutvertical openings or slots is about equal.

It has also been well known to provide metal orthodontic brackets havingbodies with vertical slots and with laminated mesh bonding pads or basesattached to the bodies. These laminated mesh bonding pads or basesinclude a shield or foil of metal laminated to a wire mesh by asintering process wherein the foil at the periphery is turned over theperiphery of the mesh. Such pads or bases are then attached to thebrackets.

It is also known to investment cast metal brackets with integral bondingpads or bases wherein such brackets would in some instances includevertical slots or openings.

Further, it is also been known to use a plastic base on a ceramicbracket as disclosed in U.S. Pat. Nos. 5,098,288 and 5,263,859 tofacilitate removal of a bracket bonded to a tooth. The latter patentalso teaches adhesively securing a bracket to a preformed plastic basewhere aligning grooves formed in the bracket and the plastic pad definean opening for receiving an auxiliary.

It has also been known as marketed by TP Orthodontics, Inc. of LaPorte,Ind., to provide a ceramic bracket having a ceramic body with a verticalopening or slot for receiving an anchoring arm of an auxiliary andhaving a heat-cured plastic bonding pad molded to the body of thebracket. These brackets are manufactured under the trademark MXi, whichis a trademark of TP Orthodontics, Inc. The bodies of these bracketshave been provided with and without vertical openings or slots.

With respect to the use of ceramic brackets by orthodontists, the demandfor brackets with vertical slots about equals the demand for bracketswithout vertical slots, as above mentioned. This requires themanufacturer to have molds for making each of the types of brackets inorder to satisfy the demand. From time to time new molds need to be madein order to produce quality brackets, and such molds are quiteexpensive. With respect to the MXi brackets made by TP Orthodontics,after the bracket body is molded, the wafer or plastic bonding base of apolymer resin is then molded onto the bracket. Accordingly, the polymerresin base is added as a bonding pad following the molding of theceramic bracket body.

The advent of light-cure adhesive for bonding appliances to teeth hasgreatly benefitted orthodontists in reducing chair time, easingchairside use by eliminating the need to mix two or more components,allowing unlimited working time because the adhesive does not set upuntil exposed to light. However, unlike chemical cure adhesives,light-cure adhesives do not cure in the dark. Heretofore, most bracketshave metal bonding bases, and when using light-cure adhesive, the curingrequires directing light at the base/tooth enamel interface. In order toget optimum curing for the strongest possible bond between metal bondingbases, light must be directed toward the mesial, distal, occlusal andgingival edges of the bonding base to cure the exposed edges of theadhesive. However, the adhesive at the center of the base does not curebecause light never reaches the center.

SUMMARY OF THE INVENTION

The bondable orthodontic appliance of the present invention eliminatesthe need to form two different appliance bodies having a bonding base orpad attached to the bodies when desired to produce brackets with orwithout openings or slots extending in any direction opposite to thearchwire receiving side of the appliance. More particularly, a slot oropening behind the archwire receiving part of the appliance can beformed in the polymer base molded to the body of the appliance forreceiving an arm of an auxiliary or a secondary archwire, whether theappliance is a bracket or a molar tube. Further the bracket may be madeof ceramic, metal or plastic. In each case where the body of theappliance is a bracket or a tube, the body of the appliance would bemade without any vertical, horizontal or diagonal opening and thatopening would then be formed in the polymer base during molding the baseonto the body of the appliance. Thus, where brackets would be providedof ceramic material, only a single mold would be needed to make theceramic bracket body, as where an opening is desired it would be formedin the base. It will be appreciated that one or more openings may beprovided to extend vertically, horizontally, or diagonally.

In an orthodontic appliance having a metal appliance body, the inventionprovides the advantage of only needing to form a single metal body andthen thereafter molding an optically clear or translucent bonding pad orbase to the body with or without vertical, horizontal or diagonalopenings. Since the base is light-permeable, it allows light to reachfurther under the base to produce a stronger bond. There is no need toilluminate the edges of the base as the light may be directed on top ofthe base, thereby significantly reducing curing time. Preferably, thebonding face of the base has a meshlike architecture to provide bettermechanical interlock.

Additionally, by incorporating a polymer resin bonding pad or base withthe metal body of an appliance, and particularly to a bracket or tubewhere no vertical, horizontal or diagonal slot or opening is needed inthe base, the in-out compensation and profile of the bracket or tube issignificantly reduced as the bracket or tube body is partially embeddedin the polymer resin base rather than being attached on top of the baseas when using a metal mesh base. A lower profile substantially reducesthe chances of occlusal interference and bond failures, as well asimproving hygiene and tissue health. A bondable tube also eliminates theproblems associated with tubes mounted on bands. And where light-cureadhesive is used to bond the appliance to a tooth, the polymer resinbase being translucent or optically clear, allows the curing light topenetrate beneath the appliance body to enhance the bonding strength.

Further, the number of steps required for making such a bracket or tubewith a resin base are substantially less than the number of steps neededto make a bracket or tube with a metal bonding pad or base.

Moreover, the use of an optically clear or translucent polymer base on abondable metal appliance body reduces the amount of metal exposedthereby greatly improving the cosmetic appeal or aesthetics of theappliance. Finally, when using light-cure adhesive or cement, inasmuchas the bonding base or pad now is either optically clear or translucent,penetration of the curing light between the metal appliance body and thetooth enamel surface is substantially greater thereby substantiallyincreasing the bond strength of the appliance to a tooth. This decreasesthe possibility of loosening during the treatment process.

According to the present invention, the method employed in making anorthodontic appliance, which includes a body of metal, ceramic orplastic having a buccal/labial archwire receiving side and a lingualside, includes preparing the appliance body and molding a polymer resinbonding base onto the lingual side of the body such that at least partof the body is embedded in the base. At least one opening extendingtherethrough may be molded in the base for receiving an anchoring arm ofan auxiliary appliance or a secondary archwire.

The method of making an orthodontic appliance according to the inventionincludes the steps of first making an orthodontic appliance body ofmetal, ceramic or plastic, cleaning the surface of the appliance bodywhere needed, subjecting the body to an adhesion-promoting process, andthen molding either a light-curable or heat-curable polymer resinbonding base onto the lingual side of the body that may have at leastone opening extending through the body thereby defining a one-pieceorthodontic appliance. The polymer resin base may be acrylic, epoxy, orepoxy/acrylic in the form of an acrylic-based epoxy, and which is eitherlight curable or heat curable.

Another embodiment of the invention is to form the orthodontic applianceof an appliance body and a polymer resin bonding base molded onto thebody, and providing the appliance body and bonding base with matchinggrooves that coact to form a vertical slot or opening.

It is therefore an object of the present invention to provide anorthodontic appliance of the bracket or tube type from a standardbracket or tube appliance body and a polymer resin base with or withoutopenings in the base to thereby reduce manufacturing costs associatedwith making one appliance without openings and another with openings.

Another object of the present invention to provide an orthodonticappliance including an appliance body of metal, ceramic or plastic and aheat or light-curable polymer resin bonding base molded onto the bodyand having at least one opening extending therethrough for receiving anarm of an auxiliary appliance or a secondary archwire.

A further object of the present invention is to provide an orthodonticappliance including an appliance body and a polymer resin bonding basemolded to the body having at least one opening through the base forreceiving an auxiliary or a secondary archwire.

A still further object of the present invention is to provide anorthodontic appliance having a metal appliance body and a polymer resinbonding base molded to the body that reduces the in-out compensation andthe profile height of the appliance, and wherein the polymer resinbonding base may be optically clear or translucent to enhance theaesthetics of the appliance.

A still further object of the present invention is to provide anorthodontic appliance having a metal appliance body and a polymer resinbonding base molded to the body that reduces the in-out compensation andthe profile height of the appliance, and wherein the polymer resinbonding base may be optically clear or translucent to increase the bondstrength when bonded to a tooth with a light-cure adhesive.

Other objects, features and advantages will be apparent from thefollowing detailed disclosure taken in conjunction with the accompanyingsheets of drawings where like reference numerals refer to like parts.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an orthodontic appliance according tothe present invention including an appliance body having a polymer resinbonding base molded to the body with a vertical opening through thebonding base;

FIG. 2 is a vertical sectional view taken through the bracket of FIG. 1and substantially along line 2-2 thereof;

FIG. 3 is a horizontal sectional view taken through the bracket of FIG.2 and substantially along line 3-3 thereof;

FIG. 4 is a perspective view of a bracket and bonding pad like that ofFIG. 1 but illustrating the opening through the bonding base to beextending horizontally;

FIG. 5 is a vertical sectional view taken through the appliance of FIG.4, and substantially along line 5-5 thereof;

FIG. 6 is a horizontal sectional view taken through the bracket of FIG.5, and substantially along the line 6-6 thereof;

FIG. 7 is a front elevational view of further modified bracket of theinvention and illustrating in phantom both vertically and horizontallyextending openings in the base;

FIG. 8 is a front elevational view of a further modified bracket of theinvention and illustrating in phantom a diagonally extending opening inthe base;

FIG. 9 is a perspective view of a still further modified bracket of theinvention showing a vertically extending opening that is formed bymatching grooves in the base and the appliance body;

FIG. 10 is a vertical sectional view taken substantially along line10-10 of the bracket in FIG. 9; and

FIG. 11 is a horizontal sectional view taken substantially along line11-11 of the appliance of FIG. 9;

FIG. 12 is a rear or back side view of the bracket body of theembodiment of FIGS. 9 to 11 prior to molding a bonding base on thebracket body to illustrate the groove formed in the bracket body thatcoacts with the groove formed in the polymer resin bonding base duringmolding the base on the bracket body.

DESCRIPTION OF THE INVENTION

The present invention relates to a bondable orthodontic appliance havinga polymer resin base or pad. The orthodontic appliance includes anappliance body having the polymer resin base or pad molded to the body.While the drawings show the appliance body as a bracket having anarchwire receiving side and a lingual side, it should be appreciatedthat the appliance body may be in the form of a buccal tube which alsohas an archwire receiving side and a lingual side. Also, while theappliance body illustrated in the drawings is in the form of an edgewisebracket having a substantially horizontally extending open archwirereceiving slot and ligature receiving tie wings, it should beappreciated that the appliance body may have one or more sets of tiewings, or it may have an appliance body of the self-ligating type.Further, the appliance body may be formed for mounting on thebuccolabial surface of a tooth or on the lingual surface of a tooth.Where the appliance body is in the form of a molar tube, it will beappreciated that any type of a molar tube configuration may be used.

It should also be appreciated that the appliance body, while having apolymer resin base or pad molded to the body, may be of any suitablematerial such as ceramic, metal or plastic of the types heretoforeknown. For example, according to the invention an orthodontic appliancecould include a ceramic appliance body onto which the polymer resin baseor pad is molded to define a bondable orthodontic appliance. Also, theappliance body could be of metal with a polymer resin base molded ontothe lingual side of the body. Finally, the appliance body could be madeof a suitable plastic such as a polycarbonate and have a polymer resinbase or pad molded onto the lingual side of the base or body.

It should also be appreciated that the polymer resin employed for makingthe base or pad may be an acrylic resin, an epoxy resin, anepoxy/acrylic resin (acrylic-based epoxy), or any other suitablemoldable polymer resin capable of bonding to the lingual side of anappliance body to provide the bond strength to resist separation duringuse and also be compatible with a bonding adhesive or cement. It shouldalso be appreciated that the polymer resin may be heat-curable orlight-curable, although it is preferably light-curable.

Referring now to the embodiment of FIGS. 1 to 3, an orthodonticappliance, generally indicated by the numeral 15 according to theinvention, includes an appliance body 17 and a polymer resin base or pad19.

The appliance body 17 includes an archwire receiving side 21 and alingual side 22. In the illustrated embodiment, the archwire receivingside of the body 17 includes a horizontally extending and buccolabiallyopening archwire slot 24 and upper and lower tie wings 25 and 26. Asabove mentioned, the archwire receiving side of the appliance body maytake any number of forms including but not limited to the Tip-EdgeBracket sold by TP Orthodontics, Inc. “Tip-Edge” is a trademark owned byTP Orthodontics, Inc. Moreover, as above mentioned, the material of theappliance body may be ceramic, metal or plastic.

The polymer resin base 19, as above noted, may be of any suitable resin,including an acrylic resin, an epoxy resin, or an acrylic-based epoxyresin, which is molded to the lingual side 22 of the appliance body suchthat at least part of the lingual side of the appliance body is embeddedin the polymer resin base to enhance the bond strength, as seen by theperipheral lip 27, shown most clearly seen in FIGS. 2 and 3, where thelip overlaps a part of the appliance body to assure that the base isproperly bonded to the appliance body to withstand the forces applied tothe appliance body by the main archwire and/or an auxiliary or secondaryarchwire during use by a patient.

When molding the polymer resin base onto the appliance body, an openingor slot 30 may be molded into the base by placement of a suitable formin the resin before curing. In this embodiment, the opening 30 extendsvertically and particularly for receiving an arm 32 of an auxiliary.While the cross-sectional shape of the arm 32 is shown to berectangular, it should be appreciated it could be round or of anothercross-sectional shape. Moreover, the opening 30 could likewise have around cross section or some other cross section. In the embodimentillustrated, a part of the opening is formed by the lingual surface ofthe appliance body 17, although it could be totally formed in the base.The bondable face of the base 19 is preferably arcuate as illustrated inorder to conform to an arcuate surface of a tooth. Further, the outerperiphery of the base being greater than the outer periphery of theappliance facilitates the transmission of a curing light when bondingthe appliance to a tooth with a light-cure adhesive.

As also mentioned above, the polymer resin after being molded onto thelingual side of an appliance body would be heat-cured if the resin is ofthe heat-curable type or light-cured if the resin is of a light-curabletype.

Further, where it would be desired to omit the vertical opening for anauxiliary arm, the vertical opening would not be molded into the baseduring the molding of the base on to the lingual side of the appliancebody.

With respect to the embodiment of FIGS. 1 to 3, as well as the otherembodiments of the invention, and whether the appliance body is abracket or a molar tube, it will be appreciated that the appliance bodyis suitably prepared prior to molding the base onto the body so as toprovide the best possible bond between the base and body.

With respect to the method of making an appliance with a metal orceramic appliance body, the appliance body is first cleaned and polishedand the surface of the body is activated to enhance the bond strengthbetween the polymer resin base and the body. Activation of the appliancebody includes dipping the body in a silane solution, curing the silanecoating with heat, and then coating the appliance body with an acrylicpolymer solution. After applying this coating, the coating is suitablycured and this coating process promotes the adhesion between the polymerresin and the appliance body when molding the polymer resin base ontothe body. Thus, the bond strength between the base and the body issubstantially increased to inhibit separation of the base from the bodyduring use.

Where the appliance body is ceramic and a bracket, a metallic oxide isincluded in the polymer resin, as disclosed in co-pending applicationSer. No. 10/120,052 filed Apr. 10, 2002, now U.S. Pat. No. U.S. Pat. No.6,786,720, and also owned by the assignee of this application.

Where the appliance body is a bracket of metal, the polymer resin may beoptically clear or translucent to allow penetration of the curing lightbeneath the appliance body and enhance the bonding of a light-cureadhesive used to bond the appliance to a tooth.

It should be further appreciated that inasmuch as the polymer resin baseis molded to the lingual side of the appliance body and with a curvatureto match that of a tooth, the lingual side of the appliance body neednot have a curvature and may be planar in shape which will facilitatethe manufacture of the appliance body.

It should further be appreciated that the orthodontic appliance with thepolymer resin base may be bonded to a tooth chemically or mechanicallyand that the bonding surface of the base will preferably be roughened orformed with undercuts or a mesh-like structure to further enhance thebond strength of the adhesive or cement used to bond the appliance to atooth. Preferably, a light-cured adhesive would be used, the curing ofwhich is facilitated by the optically clear or translucent polymer resinbase of the appliance of the invention.

The appliance is made by first making an orthodontic appliance bodyhaving an archwire receiving side and a lingual side. The polymer resinis injected into a cavity having the desired shape of the base. Theappliance body is then placed into the resin such that part of the bodyis under the level of the resin to produce an appliance with part of thelingual side being embedded in the body. Suitable forms would be placedin the resin to mold one or more openings in the base if an opening isdesired. The resin would then be cured to complete the base formationstep.

Referring now to the embodiment of FIGS. 4, 5 and 6, an orthodonticappliance, generally indicated by the numeral 15A, differs from theembodiment of FIGS. 1 to 3 only in that the opening or slot in the baseextends horizontally instead of vertically. This embodiment includes ingeneral an appliance body 35 of the same type illustrated in theembodiment of FIGS. 1 to 3 and a polymer resin base 37 provided with ahorizontally extending opening 39 at the lingual side of the appliance.As in the embodiment of FIGS. 1 to 3, the cross-sectional shape of theopening is rectangular and one side of the opening may be of anysuitable cross-sectional shape. In this embodiment the horizontallyextending opening in the base may receive a secondary archwire 42 asshown. When molding the base on a Tip-Edge Bracket body, and including ahorizontal opening, the opening can also accommodate a levelingarchwire, as described in the co-pending application Ser. No.10/177,951, now U.S. Pat. No. 6,682,345, filed Jun. 21, 2002, also ownedby the assignee of this application.

It will be further understood that multiple openings or slots may beformed in the polymer resin base if desired, and such an embodiment isshown in FIG. 7, wherein the appliance is generally indicated by thenumeral 15B. This appliance includes a vertical opening that can beutilized for an anchoring arm 43 of an auxiliary, as shown in phantom,or a horizontal opening for a secondary archwire 44 that is shown inphantom.

As previously mentioned, the opening in the base may even extenddiagonally, as illustrated in the appliance indicated by the numeral 15Cin FIG. 8. In this embodiment, a diagonal opening is formed in the baseto receive a diagonally extending arm 46 of a suitable auxiliary. Theangle of the opening relative to the vertical axis of the appliance maybe selected in accordance with the desired function to be employed withthe particular appliance and an auxiliary.

Referring now to FIGS. 9 to 12, a further orthodontic applianceaccording to the invention is shown and generally designated by thenumeral 50, and which generally includes an appliance body 52 and apolymer resin base 54. While the appliance body 52 is of a differentform than those shown in the embodiments of FIGS. 1 to 8, thisembodiment differentiates primarily from the other embodiments in thatthe opening for receiving an arm of an auxiliary is formed by matchinggrooves in the appliance body and the base. Further, the appliance bodyis of the true twin tie wing type and includes tie wings 57 and 58, eachof which includes upper and lower tie wing tips. Additionally, the lowertie wing tip of the tie wing 57 includes a ball hook 60.

The appliance body 52 includes an archwire receiving side 62 and alingual side 64 to which the polymer resin base 54 is molded, aspreviously explained with the other embodiments.

The lingual side 64 of the appliance body 52 is arcuately formed inaccordance with the expected curvature of the tooth on which it would bemounted. Similarly, the polymer resin base 54 includes an arcuatelyformed lingual surface to conform to the surface of a tooth on which isit mounted. As in the other embodiments, the bonding face of the basemay have a mesh-like surface in order to enhance the bonding to a tooth.

A vertically extending opening, generally designated by the numeral 66,for receiving an arm 67 of an auxiliary is formed by matching grooves inthe appliance body and the base. A groove 70 is formed in the appliancebody, while a groove 72 is formed in the base, which together coact todefine the vertical opening 66. During the molding of the base onto thelingual side of the appliance body, a suitable pin is laid in the groove70 of the appliance body and which then forms the groove 72 in the baseto produce the opening 66. Preferably, the lower end of the groove 70 isflared at 74 and similarly the lower end of the groove 72 of the basewould be flared to provide a flared opening for facilitating theinsertion of an arm of an auxiliary. Similarly, the upper end of thegrooves might be flared if so desired.

It will be understood that modifications and variations may be effectedwithout departing from the scope of the novel concepts of the presentinvention, but it is understood that this application is to be limitedonly by the scope of the appended claims.

1. An orthodontic appliance for shipment to a user including a metalappliance body having a buccal/labial archwire receiving side and alingual side, said archwire receiving side of said body including atleast one tie wing having a labial profile, and said lingual side ofsaid body including a base portion having a lingual profile, aconnecting portion between the base portion on the lingual side and thetie wing, the lingual profile of the base portion being substantiallyequal to the labial profile of the tie wing, and a light-permeable, heator light-cured polymer resin bonding base molded onto the lingual ofsaid base portion of said body and including an integral peripheral lipoverlapping a part of the base portion to enhance the bonding of thebonding base to the base portion of said body and having substantiallythe same lingual profile as the lingual profile of said base portionwherein the light-permeable base enhances the use of and curing of alight-cure adhesive by allowing the curing light to penetrate beneaththe appliance when bonding the appliance to a tooth to substantiallyincrease the bond strength of the appliance on a tooth.
 2. Theorthodontic appliance of claim 1, wherein the polymer resin base isacrylic, epoxy or acrylic-based epoxy.
 3. The orthodontic appliance ofclaim 1, wherein the appliance is a bracket or a tube.
 4. A method ofmaking an orthodontic appliance for shipment to a user including a bodyof ceramic, metal, or plastic having a buccal/labial archwire receivingside and a lingual side, and said archwire receiving side of said bodyincluding at least one tie wing having a labial profile, and saidlingual side of said body including a base portion having a lingualprofile, a connecting portion between the base portion on the lingualside and the tie wing, the lingual profile of the base portion beingsubstantially equal to the labial profile of the tie wing, alight-permeable polymer resin bonding base molded onto the lingual ofsaid base portion of said body and including an integral peripheral lipoverlapping part of the base portion to enhance the bonding base to thebase portion of said body and having substantially the same lingualprofile as the lingual profile of said base portion said methodcomprising the steps of: making an orthodontic appliance body ofceramic, metal, or plastic of one size such that when a bondablelight-permeable polymer resin base is molded to the lingual side of thebody the base includes an integral peripheral lip overlapping a part ofthe appliance body, wherein a bondable orthodontic appliance is producedfor shipment to a user for bonding to a tooth, and said body having anarchwire receiving side and a lingual side on which the base is molded,and molding a light-permeable, light-curable or heat-curable polymerresin bonding base to the lingual of said base portion of said body suchthat the lingual side at least partially overlaps the base and aperipheral lip is formed at the perimeter of the appliance body therebyenhancing the bonding of the bonding base to the base portion of saidbody wherein the light-permeable base enhances the use of and curing ofa light-cure adhesive by allowing the curing light to penetrate beneaththe appliance when bonding the appliance to a tooth to substantiallyincrease the bond strength of the appliance on a tooth.
 5. Anorthodontic appliance for shipment to a user including an appliance bodyof metal, ceramic, or plastic, having a buccal/labial archwire receivingside and a lingual side, said archwire receiving of said body includingat least one tie wing having a labial profile, and said lingual side ofsaid body including a base portion having a lingual profile, aconnecting portion between the base portion on the lingual side and thetie wing, the lingual profile of the base portion being substantiallyequal to the labial profile of the tie wing, a light-permeable, heat orlight-cured polymer resin bonding base molded onto the lingual of saidbase portion of said body and including an integral peripheral lipoverlapping a part of the appliance body, said integral peripheral lipassuring the base portion to enhance the bonding of the bonding base tothe base portion of said body and having substantially the same lingualprofile as the lingual profile of said base portion to withstand theforces applied to the body by an archwire during use by a patient, andsaid appliance further including a first groove formed in said appliancebody and a second groove formed in said base coacting with said firstgroove to define an opening for receiving an arm of an auxiliaryappliance or a secondary archwire for applying a predetermined force toa tooth on which the appliance may be mounted, wherein thelight-permeable base enhances the use of and curing of a light-cureadhesive by allowing the curing light to penetrate beneath the appliancewhen bonding the appliance to a tooth to substantially increase the bondstrength of the appliance on a tooth.